Gun head space takeup elements



NOV. 19, 1968 PACHMAYR ET AL 3,411,405

GUN HEAD SPACE TAKEUP ELEMENTS 2 Sheets-Sheet 1 Filed Dec. 29, l966 1 Em: 1 EWWEV H O //I ,w N FTMHIHM NH l E E. Q E 0 0m @m a E RVE y mi w i DY NOV. 19, 1968 PACHMAYR ET AL 3,411,405

GUN HEAD SPACE TAKEUP ELEMENTS Filed Dec. 29, 1966 2 Sheets-Sheet 2 l I I 1 I I I 5186 212a 42 P7 38a 44a 49 Eon/42D .B M 11.1.52

07 TOEA/E Y United States Patent 3,411,405 GUN HEAD SPACE TAKEUP ELEMENTS Frank A. Pachmayr and Edward B. Miller, Los Angeles, Calif., assignors to Pachmayr Gun Works, Inc., Los Angeles, Calif., a corporation of California Filed Dec. 29, 1966, Ser. No. 605,826 Claims. (Cl. 89-196) ABSTRACT OF THE DISCLOSURE A gun including a barrel having a breech end into which a cartridge is insertible forwardly to a firing position, a shoulder in the barrel engageable with the cartridge and limiting its forward movement into the barrel, a slide mounted to recoil rearwardly relative to the barrel and to feed a cartridge forwardly into the barrel upon returning relative forward movement, and a head space take-up structure carried by the slide and constructed to exert yielding force forwardly against a cartridge in the barrel in a relation urging the cartridge slightly forwardly as far as possible in the barrel.

This invention relates to certain improvements in the structure of guns, and particularly to means for enhancing the effectiveness and reliability with which the firing pin of a gun strikes the firing cap of a cartridge to produce ignition of the propellant charge. The invention will be described primarily as applied to a well known type of automatic pistol having a slide which retracts relative to the receiver of the gun and an associated barrel upon firing.

In a gun of the type with which the present invention is concerned, the cartridge to be fired is inserted forwardly into the breech end of the barrel, to a firing position, with the recoilable slide being disposed across the rear end of the cartridge and barrel. At the time of firing, the cartridge is thus confined axially between a rearwardly facing shoulder formed in the barrel and a forwardly facing shoulder on the slide. However, this confinement is not normally precise enough to avoid the development of some head space or play of the cartridge between its retaining shoulders. That is, the cartridge cannot normally be in simultaneous contact with both of these shoulders, and as a result the cartridge invariably is free for some slight axial movement between its positions of engagement with the forward and rearward motion limiting shoulders.

This imprecision and unreliability in the positioning of the cartridge at the time of firing may result in poor or non-uniform ignition of the cartridge primer by the firing pin, and associated unreliable firing characteristics of the gun as a whole. This is true because, if the cartridge happens to be in a position in which it does not about directly against the shoulder in the barrel which limits forward movement of the cartridge, actuation of the firing pin against the cartridge may actually shift the cartridge slightly forwardly against its stop shoulder at the time of firing. Because of this movement of the cartridge, even though slight, the effective striking action of the firing pin against the primer cap is less abrupt and sharply defined than would be desired, and may result in weak ignition and poor explosion of the primer. At the time of firing the next cartridge, on the other hand, the cartridge may initially be in its forwardmost position, so that a very effective striking action by the firing pin is attained. Consequently, the firing of the gun may be very non-uniform and produce non-uniform projectile ejection characteristics even though all other moving of parts of the gun may be entirely consistent in their movements and operation.

A major object of the present invention is to provide 3,411,405 Patented Nov. 19, 1968 improved structures for eliminating the possibility of any freedom for substantial motion of the cartridge relative to the barrel and slide in the firing condition, and to thereby render the ignition characteristics of the gun completely uniform and unaffected by any head space factor. For this purpose, I provide a head space take-up structure, preferably carried by the slide, which acts to remove any play from the mechanism of the gun, and on each operation of the gun functions to assure displacement of the cartridge as far forwardly as it can move, and into engagement with the stop shoulder in the barrel, so that the firing pin cannot cause further displacement of the cartridge but will always strike the cartridge cap with maximum sharpness and effectiveness. Preferably, the take-up structure includes means exerting a yielding force forwardly against the cartridge, and for best results including a spring for applying that force. In one form of the invention, the slide may carry a cartridge engaging part at a location of extension through the forwardly facing cartridge engaging surface or shoulder of the slide, with a spring yieldingly urging the specified part and the engaged cartridge forwardly to the limit of its motion. In another form of the invention, an elongated spring element of wire form or the like may form a finger for exerting the desired yielding force against the cartridge.

The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings, in which:

FIG. 1 is a side view of a gun embodying the invention;

FIG. 2 is a greatly enlarged vertical axial sectional view through a portion of the FIG. 1 gun, with the gun illustrated in its battery or firing position;

FIG. 3 is a view similar to FIG. 2, but showing the parts in recoiled positions;

FIG. 4 is a fragmentary vertical transverse section taken on line 44 of FIG. 3;

FIG. 5 is a fragmentary vertical section through the head space take-up portion of a variational form of the invention;

FIG. 6 is a horizontal fragmentary section taken on line 66 of FIG. 7;

FIG. 7 is a rear view taken on line 77 of FIG. 5;

FIG. 8 is a view similar to FIG. 5, but showing another form of the invention;

FIG. 9 is a vertical section taken on line 9-9 of FIG. 8;

FIG. 10 is a view similar to FIG. 5, but showing still another form of the invention; and

FIG. 11 is a vertical section taken on line 1111 of FIG. 10.

In FIG. 1, I have shown a conventional type of automatic h-and gun 10, of a type adapted to fire sequentially a series of cartridges or rounds 28 contained within a magazine 12 which is inserted upwardly into the handle portion 13 of the receiver 14 of the gun. At its upper side, receiver 14 movably carries a recoilable slide 15, which is mounted by conventional horizontally elongated guideways 16 (FIG. 4) for horizontal sliding movement relative to receiver 14 along the axis 17 of FIG. 1, and between the battery position of FIGS. 1 and 2, and the recoiled or retracted position of FIG. 3. At its forward end, slide 15 carries a conventional bushing 18 which is disposed about and locates a tubular gun barrel 19, and is reciprocable with the slide relative to receiver 14 and barrel 19 between the FIGS. 1 and 3 positions. The rearward recoiling movement of the slide and its carried bushing and other parts is resisted by a coil spring 19' contained within the receiver and slide, and disposed about a horizontal axis 20, with this spring exerting forward force against the slide and rearward force against the receiver in a well known conventional manner.

The forward portion of the barrel is as previously mentioned located by bushing 18. The rear portion of the barrel is mounted by a vertically extending link 21 (FIG. 2) for limited rearward and downward swinging movement between the battery position of FIG. 2 and the retracted recoil position of FIG. 3. For this purpose, link 21'is pivotally connected by a lower horizontal transverse pin 22 to the receiver, and by an upper transverse horizontal pin 23 to a lug 24 projecting downwardly from and integral with the barrel. Barrel 19 has at its upper side two upwardly projecting semi-circular ribs 24' and 25 which are engageable with coacting shoulders or ribs formed at the inner side of the slide, in the battery position of the barrel, to locate the barrel relative to the slide.

The forward portion of the slide is of course hollow to receive the barrel in its illustrated positions within the slide. This barrel receiving space Within the front of the slide, however, terminates rearwardly at the location of a vertically extending forwardly facing shoulder surface 26 (FIG. 2) formed by the material of the slide axially opposite the rear open end 27 of the barrel, with shoulder surface 26 being disposed substantially perpendicular to the axis 17 of the barrel in its battery position. In a conventional gun of the present type, when slide 15 moves forwardly from its FIG. 3 position to its FIG. 1 position, shoulder surface 26 engages the rear surface 40 of the next successive cartridge 28 in magazine 12, and shifts that cartridge forwardly into the barrel toward the FIG. 2 position. For firing the cartridge, there is provided in the rear portion 29 of slide 15 a firing pin 30, mounted Within an axial passageway 31 for sliding movement for wardly and rearwardly under the influence of hammer 32, with the firing pin having a forwardly projecting portion 33 adapted to extend through a reduced dimension opening 34 to strike the central primer cap portion 35 of the cartridge. For limiting the extent to which cartridge 28 may be shifted forwardly into barrel 19, this barrel contains and forms a narrow annular rearwardly facing shoulder 36, which is engageable with a corresponding narrow annular forwardly facing shoulder 37 on the cartridge case.

The portions of the apparatus thus far described are completely conventional. The novelty of the present invention resides in the provision in combination with these parts of a head space take-up element 38, for the purpose of taking up play between cartridge 28 and its motion limiting shoulders. In FIG. 2, it will be apparent that cartridge 28 does not simultaneously engage both the forward motion limiting shoulder 36 within the barrel and the rearward motion limiting shoulder 26 of the slide, and as a result a substantial amount of axial head space or play remains, as indicated at 39. That is, cartridge 28 may shift through the distance represented at 39 from a position of engagement with shoulder 36 to a rearward position of engagement with shoulder 26 of the slide. To always assure that the cartridge will be in the illustrated forwardmost position within this range of possible movement, 'head space take-up element 38 exerts a yielding force forwardly against the rear end surface 40 of the cartridge. For this purpose, element 38 may take the form of a plunger having an externally cylindrical first portion 41 slidably received and closely confined within an axially extending cylindrical passage 42 in the slide, and carrying a forwardly projecting reduced diameter portion 43 whose forward end may be annularly rounded as shown and projects slightly forwardly beyond the plane of vertical slide shoulder 26. The plunger is yieldingly urged forwardly by a coil spring 44 received within passageway 42 to the rear of the plunger, with the forward motion of the plunger being limited by engagement of enlargement 41 of the plunger with an annular reduced diameter flange 45 formed about portion 43.

This flange 45 may typically be formed by annularly staking the material of the slide inwardly to the illustrated condition. Preferably, portion 43 of the plunger in its forwardmost position projects beyond the plane of surface 26 a distance between about .050 and .060 of an inch.

In using the gun of FIGS. 1 to 4, assume first of all that the gun is initially in its battery condition of FIGS. 1 and 2, with a cartridge 28 contained within the breech end of the barrel, as shown. In this condition, plunger 38 holds the cartridge forwardly against shoulder 36, so that upon firing of the cartridge, by forward actuation of firing pin 30, this pin strikes the primer of the cartridge with a solid blow to assure optimum ignition characteristics. If take-up element 38 were not present in the device, and cartridge 28 were displaced rearwardly to a position of engagement with slide shoulder 26, the forward actuation of the firing pin would first have the effect of displacing the cartridge forwardly through the distance represented at 39 in FIG. 2, and into engagement with shoulder 36, and would only then become effective to cause ignition. This motion of the cartridge would introduce into the firing process the previously discussed non-uniform ignition characteristics, or weak ignition, so

1 that the user of the gun could not rely upon as optimum firing results as when the element 38 is present.

After the propellant within cartridge 28 has been ignited, the resultant gases of combustion eject the projectile of the cartridge forwardly from the barrel, and then cause the cartridge case to recoil rearwardly against shoulder surface 26 of the slide, to move the slide rearwardly to its FIG. 3 position at which the empty cartridge case is ejected, and the next successive cartridge is fed upwardly to a position in front of shoulder surfact 26. The rearward motion of the slide causes barrel 19 to swing rearwardly and downwardly to its FIG. 3 position, while the subsequent forward motion of the slide under the influence of spring 19 then feeds the next successive cartridge into the breech end of the barrel, and ultimately causes slide surface 26 to contact the rearwardly projecting lug 46 on the barrel in a manner shifting the barrel forwardly and upwardly from its FIG. 3 position to its FIG. 1 position. Element 38 again acts to force the cartridge forwardly into abutting engagement with shoulder 36 in the barrel, in preparation for a reliable and effective ignition on the next actuation of the firing pin under the influence of the trigger.

As seen best in FIGS. 2 and 4, the plunger 38 is desirably so located as to contact a peripheral edge portion or rear transverse surface 40 of the cartridge case, desirably at the top of the case as shown. The broken line 40' of FIG. 4 illustrates the positioning of the periphery of this cartridge case relative to the location of element 38 and the centralized firing pin. As will be apparent, plunger 38 is desirably centered about and movable along an axis 47 which is parallel to the previously mentioned axis 17.

FIGS. 5 to 7 show a variational form of the invention which may be considered as identical with that of FIGS. 1 to 4 except as to the positioning and retention of head space take-up plunger 38a within slide 15a. In FIGS. 5 to 7, plunger 38a is received within a passageway 42a which extends rearwardly to the rear extremity of the slide, and opens rearwardly at 142 a. Thus, the plunger 38a and its spring 44a may be insertable into passage 42a, and removable therefrom, through the rear end of that passage, and are retained in the passage by means of a retaining plate 48, whose opposite vertical parallel edges 49 are slidably received and guided within vertical guideways or grooves 50 formed in the slide as shown. Plate 48 may be inserted upwardly into its illustrated position within the guideway grooves 50, and contains a central opening 51 (FIG. 7) through which the firing hammer may actuate firing pin 30a. Forward motion of take-up plunger 30a may be limited by engagement with an an nular shoulder 45a formed in the slide. In the FIGS. 5 to 7 arrangement, plunger 3811 may be located at the left side of the firing pin, with the usual extractor hook or member 52 being mounted within a passageway 53 at the opposite side of the firing pin. As in the first form of the invention, the axis 54 of the head space takeup plunger 38a may be disposed essentially parallel to the axis of the barrel in its battery position, and perpendicular to the vertical cartridge engaging shoulder 26a of the slide. The take-up action of plunger 38a is the same as discussed in connection with FIGS. 1 to 4, and attains the same advantageous results.

FIGS. 8 and 9 show another form of the invention which may be considered as the same as that of FIGS. 1 to 4 except for the substitution of an elongated spring wire 38b for the head space take-up element 38 and its associated parts. Wire 38b may have a mounting portion 55 extending rearwardly within a passage 56 formed in slide a, and confined against removal from that passage by upward staking or deformation of a localized portion of the wire at 57. To enable such deformation, the slide may have a drilled passage 58 extending upwardly from its bottom surface 59, and into which a staking tool may be inserted and driven.

The passage 56 within which wire 38b is received may be directly beneath and parallel to firing pin 30b. The forward end of wire 38b may be turned upwardly to form a spring finger 59 of the shape illustrated in FIG. 8, with this finger being received and movable within, but laterally confined by, a recess 60 formed in the lower portion of the forward surface 26b of the slide. Passage 56 may be enlarged at 61, so that finger 59 may be defiected slightly, and will exert a yielding force forwardly against the rear end of a cartridge. Finger 59 of course projects forwardly beyond shoulder surface 26b, and in use serves the same take-up function performed by element 38 of FIGS. 1 to 4. That is, finger 59 at all times urges each cartridge fed into the breech end of the barrel forwardly, and into engagement with the shoulder within the barrel which limits forward motion of the cartridge, so that upon actuation of the firing pin, the cartridge does not move forwardly but receives a very effective blow from the firing pin.

FIGS. 10 and 11 show another form of the invention which is less desirable than those previously described, but which attains some of the objects of the invention by provision of a rigid fixed element 380 at the fordward end of the rear portion of slide 150. Element 38c has an upwardly projecting fiat planar portion 138e, presenting a rear planar surface 62 abutting against forward face 26c of the slide, and also presenting a planar vertical forward face 63 engageable with the rear end of the cartridge. At its underside, the slide is recessed or cut away at 64 to receive a rearwardly extending mounting portion 65 of element 380, which portion is rigidly secured to the slide, as by screws 66, to secure part 380 in fixed position relative to the slide. The thickness of portion 138s of part 38c is just sufficient to take up the head space represented at 39 in FIG. 2 to always force shoulder 37 of the cartridge (FIG. 2) against shoulder 36 of the barrel, while surface 63 of element 380 simultaneously engages the rear end surface of the cartridge against any substantial axial shifting movement. Portion 1380 of element 380 may contain a central opening 69 (FIG. 11) for passing the firing pin into contact with the cartridge, and may be cut away at 70 to pass the ejector hook or pin 71 forwardly past portion 138s of element 38c.

We claim:

1. A gun comprising a barrel having a breech and into which a cartridge is insertible forwardly to a firing position, means forming a stop shoulder engageable with the cartridge in a relation limiting its forward movement into the barrel, a slide mounted to retract relative to the barrel upon firing of a cartridge therein and operable to feed a cartridge forwardly into the barrel upon returning relative forward movement, said slide having a generally vertical forwardly facing shoulder surface rearwardly opposite said barrel, a firing pin carried by the slide and adapted to move forwardly through said forwardly facing shoulder surface to engage and fire the cartridge, and a head space take-up structure carried by said slide and constructed to exert yielding force against a cartridge in the barrel in a relation urging the cartridge forwardly against said shoulder, said take-up structure including a plunger mounted slidably in a passage is the slide for limited front to rear movement relative thereto and having a portion projecting forwardly through and beyond said shoulder surface of the slide and engageable forwardly against a rear end surface of the cartridge, a spring carried by the slide within said passage and yieldingly urging said plunger forwardly in a relation causing said plunger to urge a cartridge forwardly in the barrel and against said stop shoulder, said passage extending rearwardly through said slide to a rear end thereof and opening rearwardly at that location, and a part at said rear end of the slide for retaining said spring and plunger in the passage but which is removable to enable rearward withdrawal of the spring and plunger from the passage.

2. A gun as recited in claim 1, in which said last mentioned part is mounted to the rear end of the slide across said passage and is guided by generally vertical ways in the slide for downward withdrawal from its position of disposition across the passage to thereby free the plunger and spring for removal.

3. A gun comprising a barrel having a breech end into which a cartridge is insertible forwardly to a firing position, means forming a stop shoulder engageable with the cartridge in a relation limiting its forward movement into the barrel, a slide mounted to retract relative to the barrel upon firing of a cartridge therein and operable to feed a cartridge forwardly into the barrel upon returning relative forward movement, and a head space take-up structure carried by said slide and constructed to exert yielding force against a cartridge in the barrel in a relation ur ing the cartridge forwardly against said shoulder, said take-up structure including an elongated spring element carried by the slide and forming a spring finger projecting to a position to engage said cartridge and urge it forwardly.

4. A gun as recited in claim 3, in which said spring element is movable with the slide and extends in a generally front to rear direction relative thereto and has a forward end portion forming said spring finger, said finger being turned upwardly and positioned to engage a rear end surface of a cartridge in the barrel and exert forward yielding force thereagainst.

5. A gun as recited in claim 4, in which said slide has a generally vertical forwardly facing shoulder surface rearwardly opposite said barrel, there being a firing pin carried by the slide and adapted to move forwardly through said shoulder surface to engage and fire the cartridge, said slide having a recess extending rearwardly thereinto beyond said forwardly facing shoulder surface at the lower end of said shoulder surface and adapted to at least partially receive said spring finger.

6. A gun as recited in claim 5, in which said spring element extends rearwardly from said recess within a passage in the slide and has a portion locally deformed upwardly in a relation locking said spring element in the slide.

7. A gun comprising a barrel having a breech end into which a cartridge is insertible forwardly to a firing posi tion, means forming a stop shoulder engageable with the cartridge in a relation limiting its forward movement into the barrel, a slide mounted to retract relative to the barrel upon firing of a cartridge therein and operable to feed a cartridge forwardly into the barrel upon returning relative forward movement, and a head space take-up structure formed separately from said slide and carried thereby and projecting forwardly therefrom and constructed to 7. displace said cartridge forwardly in the barrel into substantial engagement with said shoulder, said slide having a forwardly facing shoulder surface rearwardly opposite said barrel, said take-up structure being a rigid part having a first portion extending vertically in front of said shoulder surface of the slide, and having a mounting portion projecting rearwardly at the underside of the slide and secured thereto.

8. A gun comprising a receiver, a barrel having a breech end into which a cartridge of predetermined nominal size is insertible forwardly to a firing position, a slide mounted for rearward recoiling movement relative to the receiver and barrel, means mounting the breach end of said barrel to swing slightly downwardly and rearwardly relative to the receiver upon recoil of the slide, said barrel and slide being locked together in essentially fixed relative positions when in their forward battery condition, means forming a stop shoulder carried by the barrel engagea-ble with the cartridge in a relation limiting its forward motion into the barrel, said slide having a forwardly facing generally vertical shoulder surface rearwardly opposite said barrel and positioned to be received opposite and closely adjacent the back of a cartridge in said barrel, said shoulder carried by the barrel and said shoulder surface on the slide being so positioned relative to one another as to leave clearance for slight axial movement of at least some cartridges of said predetermined nominal size when the slide and barrel are in battery position, and a head space take-up structure carried by said slide and constructed, when the parts are in said battery position, to exert yielding force forwardly against a cartridge in the barrel in a relation and with a force to displace the cartridge forwardly out of contact with said shoulder surface on the slide and into tight engagement with said shoulder carried by the barrel.

9. A gun as recited in claim 8, in which said take-up structure includes a part mounted to the slide for limited front to rear motion relative thereto and engageable forwardly against a cartridge in the barrel, and a spring carried by the slide and yielding urging said part forwardly relative to the slide and against a cartridge in the barrel in a relation urging the cartridge forwardly against said shoulder carried by the barrel.

10. A gun as recited in claim 8, including a firing pin carried by the slide and adapted to move forwardly through said forwardly facing shoulder surface to engage and fire the cartridge, said take-up structure including a plunger mounted slidably in a passage in the slide for limited front to rear movement relative thereto and having a portion projecting forwardly through and beyond said shoulder surface of the slide and engageable forwardly against a rear end surface of the cartridge, and a spring carried by the slide and yieldingly urging the plunger forwardly in a relation causing said plunger to urge a cartridge forwardly in the barrel and against said stop shoulder.

References Cited UNITED STATES PATENTS 984,519 2/1911 Browning 89-163 X 1,896,820 2/1933 Jolidon 89-163 X 2,535,156 12/1950 Pastore et al. 89-196 3,287,843 11/1966 Seidel et al. 42-69 BENJAMIN A. BORCHELT, Primary Examiner. S. C. BENTLEY, Assistant Examiner. 

